Stayed in a brand new hotel last night.
Under the kitchenette sink was some sort of electrical control device fitted to a water pipe but also plugged into the mains.
About match box size with black plastic housing two rotary adjustment controls and test button.
Whatever it was about every 30minutes it clunked on emitted rushing water sounds then clunked off.
Couldn't get a decent photo due to awkward location.
The kitchenette had a washing machine and a dishwasher.
What is this infernal device and what is it's purpose other than to deny me sleep?
I turned the one in my unit off at the wall, but others were going off in unoccupied rooms either side. Long night.